Flow Control Device for Assays Using Sealed Diffusion Zone
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current flow-based assays face challenges in regulating and controlling the flow of fluid samples, leading to variability and inefficiency in immunoassay devices, particularly in quantitative assays.
Innovation Solution
A fluidic device with a water-impermeable substrate and flow channel, featuring a porous reagent pad, a porous sensor membrane separated by a free space diffusion zone, and a water-impermeable seal to direct fluid flow and enhance flow control, along with a cartridge assembly for improved assay performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flow-based assay device is used, then the device structure is simple, but the flow control of fluid samples is poor leading to variability
Solution Approach 1:
The device is divided into distinct functional zones including a sample application zone, reagent pad zone, flow control zone with diffusion barrier, and detection zone. Each zone performs a specific function in the assay process, allowing independent optimization of flow characteristics in each region while maintaining overall device functionality.
Solution Approach 2:
A diffusion barrier layer is introduced as an intermediary component between the reagent pad and detection membrane. This intermediate layer actively regulates fluid flow and analyte diffusion rates, providing precise flow control without requiring complex mechanical structures or pumps.
2Measurement precision
If the flow speed of fluid sample is not controlled, then the device operation is simple, but the assay accuracy and reproducibility deteriorate
Solution Approach 1:
The device utilizes passive flow control mechanisms where the diffusion barrier layer automatically regulates fluid and analyte movement based on concentration gradients and flow dynamics. The system self-regulates flow speed without requiring external control systems, complex operations, or user intervention, maintaining assay precision through inherent physical principles.
3Reliability
If a diffusion barrier is added to control flow, then the flow control improves, but the device complexity increases
Solution Approach 1:
The diffusion barrier is implemented as a porous layer with controlled pore size and distribution that selectively regulates analyte diffusion while allowing fluid flow. This material-based approach achieves precise flow control through intrinsic material properties rather than complex structural designs, maintaining device simplicity while improving flow reproducibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures controlled and reproducible fluid flow, reducing variability and enhancing the accuracy and efficiency of immunoassays by regulating the flow of reagents and analytes, thereby improving the detection of target analytes in fluid samples.
Implementation Method 1
the water impermeable seal directs flow of incoming fluid upstream into the sealed portion of the porous sensor membrane
Implementation Method 2
a free space diffusion zone located within the flow channel separating the porous reagent pad from the porous sensor membrane
Implementation Method 3
a porous reagent pad located within the flow channel, where the porous reagent pad includes a release zone; a porous sensor membrane located within the flow channel downstream from the porous reagent pad
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The present disclosure relates to devices and methods for detecting the presence of a target analyte in a fluid sample using an assay. A fluidic device for flow control in an assay is disclosed comprising a water impermeable substrate (300) with a flow channel (301) located on its upper surface; a porous reagent pad (305) located within the flow channel, where the reagent pad includes a release zone that comprises a mobilizable reagent component of an assay; a porous sensor membrane (306) located within the flow channel downstream from the reagent pad, where the sensor membrane is separated from the reagent pad by a free space diffusion zone and where the sensor membrane includes a capture zone that comprises an immobilized capture component of the assay; a water impermeable top support located within the flow channel and disposed over at least a portion of the sensor membrane; and a flow control medium that forms a water impermeable seal around a portion of the top support and sensor membrane, where the seal is configure to direct flow of fluid into the sealed portion of the sensor membrane.